ULTRASONIC SURFACE PARAMETERISATION USING MAXIMUM ENTROPY SIGNAL PROCESSING

This paper demonstrates the value of the Maximum Entropy Method (MEM) for assisting in the estimation of surface amplitude distributions from reflected ultrasonic pulses. Roughnesses ranging from around 2μm to over 140μm (Ra ) have been measured using LMN transducers with centre frequencies ranging from 10 to 40 MHz. Recent enhancements to the maximum entropy method give improved results, with higher resolution and a capability of quantifying an error for each deconvolution image. A selection of results from rough and layered surfaces is presented comparing the new MEMSYS 3 results with those from the original MEM and those measured by the Form Talysurf.